SILK, bc braided for good knot security & also will not migrate or get displaced. Need to use large size suture material! Bc if small size suture, need to tie tight, might cut through ductus & bleed to death asap.

How do you know where to dissect for going in to do a PDA ligation?

Go to base of heart & where you feel fremitus, that's where you dissect. There will be CT there, around the PDA. If you have angled hemostats (or curved Halsted) dissect cr & ca of the PDA & be careful w/ wide & short ones which are extra easy to damage.

How should you dissect the PDA from the surrounding CT & why must you be so careful?

Use angled hemostat/curved Halsted. Give yourself a little space when you're dissecting. If you're too close you might be peeling off layers of the wall of the PDA & you can accidentally make it too thin & it will break & start to hge. So stay away a few ml from the ductus & dissect bluntly. Then take it out to lose it so you can see what youre doing.

Once the CT is dissected around the PDA, how do you go about ligating it?

W/ vagus nn in vicinity, bluntly dissect & lift it up or down for it to be out of your way. Use stay suture. Pass forceps/Halsted’s around under ductus, grab suture material. Pull through & ligate.

Details on how to ligate the PDA - which side of the PDA do you ligate 1st? When you 1st ligate the PDA, what happens? Do you dissect?

Ligate AORTIC side 1st - when you initially ligate, there will be bradycardia (Branham sign). THEN suture pulmonary side. It is not necessary to transect the PDA once ligated. However, still a risk of it recanalizing, in which case the procedure must be repeated.

If you are closing the chest well, should you suture plura back together?

Don't have to

Do you ligate pulmonary or aortic side of PDA 1st?

AORTIC side 1st

What is the Branham sign? Prevention/what should you have in case this becomes a prob?

When you 1st ligate the PDA, the heartrate will dec (bradycardia). If tighten slowly, might be less of a problem. Atropine should be available in case bradycardia too low

What is the Jackson & Henderson modification/ how does it work?

If you are worried about bluntly dissecting around the PDA, esp if it is a short & wide one, you can use this technique to avoid this step. Just dissect ca to PDA & around the BACK of the AORTA instead. Pass the suture (extra-long & folded double) around the back of the aorta. Then dissect just Cr to the PDA. Then, from cr side of the PDA, grab the suture that's looped around the back of the aorta & pull it through. Then gently perform a sawing motion to displace suture through CT from top/back of aorta to behind the PDA. Cut looped end so now have 2 sutures for aortic & pulmonary side ligations. You are now set up to ligate as you would normally. (The braided suture can saw through CT but not the PDA)

PRAA (Persistent Right Aortic Arch)

Ligate instead of cutting bc sometimes might have both a PDA w/ a PRAA...minimal chance but to prevent any accident, ligate before cutting.

WHEN do you usually see CS of PRAA? What are main CS/vs what concurrent CS might you see?

Show CSs at weaning - usually regurg. However, might see concurrent resp signs (aspiration)

How might a PRAA appear radiographically?

May have ventral tracheal displacement on survey radiographs.

You open the chest & see the aorta, pulmonary a & the dilated esophagus. Now explain the procedure

careful to dissect PRAA from CT in its entirely. Place ligatures, can ligate either one 1st (but maybe aortic 1st just to keep in habit). You want to ligate just in case there is a persistence of the ductus. After ligating, transect the PRAA. Then dissect bluntly around the eso, bc there has been a stricture & aorta against eso has czd thickened area on surface, so debride area where stricture is to help make lumen normal again. Maybe consider passing tubes to help expand eso lumen (like bougienage)

After Sx Tx of a PRAA, how will you feed the animal?

Start w/ feeding a gruel....take a day or 2 to inc thickness/hardness of food. You might have to keep feeding them in a standing position to have gravity assist food going down eso & not pooling in stretched out portion

2 things you need to do for post-op management of PRAA after Sx Tx?

(1) Tx pneumonia if necessary(2) Elevated feeding of moist solid food - may need to continue for life

Prognosis of PRAA → what bout that megaeso?

Use long-term follow-up esophagrams to assess recovery. The Megaesophagus rarely completely reversed, but with early Sx reversal more likely. If esophagus diameter > twice normal, reversal very unlikely

When would reversal of megaeso be very unlikely?

If greater than twice the normal size

What are 2 variations in vasculature you can see when performing a PRAA correction procedure?

(1) 40 % of cases persistent left cranial vena cava(2) Also there can be hemiazygos vein (can be sacrificed if it's in ur way during Sx)

Aside from a lateral thoracotomy, how else might you approach the PRAA repair Sx?

This is a Turkel cath. The stylet (bottom thing) has a blunt end to go into cath look alike (top thing) & that cath has a 3 way stopcock pre-attached to it so you can immediately begin to use it. When you place the stylet in & you use it to pierce the thoracic wall, there is a prong on stylet. When It is being pressed on/in contact w/ something firm (like when you press on it w/ finger like on pic) there is a red band. So when enter thorax past the wall, then there is no pressure & instead of red will show green band, so you know you can slide cath in w/o czing damage. When you pull out the stylet, there is a seal so only communication via T-port.

As a rough guideline, the tube diameter must be similar to the..

Diameter of the main bronchus, OR 1/2 - 1/3 the width of the intercostal space

What do you want the consistency of the T-tube to be like?

Flexible, but not collapsible

Do you want holes in the T-tube? How many? Size?

Number of holes = no more than 3 (each additional orifice only increments the flow by 5%) (Help prevent occlusion). Size of holes = 1/4 the diameter of the tube (diameter > 1/3 cz weakness & predispose for kinking)

Dogs & cats 3-6 kg should probably have a tube size of...

Tube 14-16 Fr.

Dogs 7-15 kg should probably have a tube size of...

Tube 18-20 Fr.

Dogs 16-30 kg should probably have a tube size of...

Tube 22-28 Fr.

Dogs > 30 kg should probably have a tube size of...

Tube 30-36 Fr

Explain a way you can get a really good seal when placing a thoracostomy tube

Grab skin & pull taught in cr direction, make stab incision at level of IC space that space you want tube to go in. Then bluntly dissect. Push cath through incision. Then when release skin that was pulled forward to go back into normal position, will slide down & the incision will no longer be over the incision that is in the IC space & the skin will adhere like a tight glove

When you are pushing the tube into the thorax you need to hold the tip of the tube w/ an instrument - what is the proper way to hold it?

Grab from below, not from above. If from above, rubber is in the way & it rebounds off the wall & you cant pierce it. You want to grab from under w/ tips slightly forward so you can pierce wall.

If you have a PTx that weighs less than 15 kg, what can you use as means of suction?

Syringe w/ a 3-way stopcock

If you have a PTx that weighs more than 15 kg, what can you use as a means of suction?

Heimlich valve

PRE (Pulmonary Re-expansion Edema) happens bc of what? How can you help prevent this?

(1) Drainage reduced to a volume that is consistent w/ the 1 produced by the tube itself: 2 ml/kg/day.(2) X-ray at 24 hrs. Does not show air or free fluid(3) When collection of fluid is 50 cm3 or less in 24 hrs (these numbers are for a 20kg dog)

**How much fluid is produced in the thorax as a Rxn to the tube being in there?

If there is a CHRONIC chylothorax, what is really the only way to try to fix it?

Pleuroperitoneal shunt. Puts elastic tube through diaphragm & using valves that are placed SQ so owner can push several times a day & drain from thorax into abdomen. Basically lets you buy some good quality of life for the PTx. multifenestrated shunt.